Cryogenic connection enclosure

ABSTRACT

Cold enclosure having a tubular shape, surrounding the conductors of a cryogenic connection, consisting of two layers of composite material, joined together by a metallic connection, an outer cover made of an iron and nickel alloy in which the proportion of nickel comprises between thirty and forty per cent, and an inner layer of copper or aluminum, this inner layer preventing the generating of alternating induced fields in the outer cover, which is magnetic.

United States Patent 11 1 Aupoix et al.

[111 3,715,453 1 Feb. 6, 1973 [54] 'CRYOGENIC CONNECTION ENCLOSURE [75] Inventors: Marcel Aupoix, Paris; Francois Moisson-Franckhauser, Bretignysur-Orge, both of France [73] Assignee: Compagnie Generale dElectricite,

Paris, France 22 Filed; April 20,1972 21 Appl. No.: 246,018

[30] Foreign Application Priority Data April 28, 1971 France ..7115182 [52] US. Cl ..l74/15 C, 138/143, 174/36, 174/106 R, 174/126 CP, 174/DIG. 6,

v 335/216 [51] Int. Cl. ..H0lb 7/34, H0lv 11/00 [58] Field of Search ..174/15 R, 15 C, 36, DIG. 6,

174/102 A, 106 R, 126 GP; 335/216; 138/140,141,142,143,151,152,170,171; 285/D1G. 5

[56] References Cited UNITED STATES PATENTS I 3,621,883 ,11/1971 Miller ..138/143 3,598,156 8/1971 Ulmer et a1 ..l38/140X 3,595,982 7/1971 Kafka ...l74/DlG 6 3,512,581 5/1970 Lawton ..174/15 C 2,063,325 12/1936 McLeod ..138/140 OTHER PUBLICATIONS Design for a Superconducting AC. Power Cable, Proc. IEEE, Vol. 118, No. 10, Oct. 71, pp. 1493-1500.

Primary Examiner-Hemard A. Gilheany Assistant Examiner-A. T. Grimley Attorney'Richard C. Sughrue et al.

[5 7 ABSTRACT Cold enclosure having a tubular shape, surrounding the conductors of a cryogenic. connection, consisting of two layers of composite material, joined together by a metallic connection, an outer cover made of an iron and nickel alloy in which the proportion of nickel comprises between thirty and forty per cent, and an inner layer of copper or aluminum, this inner layer preventing the generating of alternating induced fields in the outer cover, which is magnetic.

4 Claims, 1 Drawing Figure PATENTEDFEB s 1915 r l ORYOGENIC CONNECTION ENCLOSURE BACKGROUND OF THE INVENTION IIField of the Invention The present invention concerns a composite tubular -cold container surrounding the conductors of a cryogenic connection, these conductors carrying an alternating current or a direct current comprising a residual wave.

2. Description of the Prior Art -'Theproducing of cryogenic connections in which the conductors are'contained in a cold container, this cold container carrying a cooling fluid, is known in the car- 'rying'of high electric power. In the case of a cryogenic connection having an; invariable length, the conductors can consist of invariable cables, andthe cold contain'er which' surrounds them of an iron and nickel alloy having low relative thermal contraction, comprising 30 to 45 per cent of nickel. This'-is,.for example, the case of an alloy k;nown*by its trade name INVAR,

-produced andcommercialized in France by Messrs.

Metallurgy d lmphy.

- The use of conductive casing to reduce losses caused byinduced currents in the vicinity of cables is also known. An electric screen-common to a cable or to a group of cables canfalso be adopted in a conventional way.

These various devices undergo athermal contraction when theyare cooled,andmust be arranged either in a helical configuration, or in the form of corrugated tubes.

,TlIlS"C0ld contalner, whose magnetic permeability is a high, is the seat of electromagnetic losses due to induced alternating currents.

The-aim of the present inventionis to overcome this disadvantage.

SUM-MARY OF THE INVENTION The object of the present invention is a cold container made of a composite material, having a tubular shape, surrounding theconductors of a cryogenic connection, comprising a casing made of an iron and nickel -alloy whose nickel concentration is comprised between "a'nd 45'percent, characterized in that a metal screen having a resistivity lower than 3.10 ohms. meter surrounds the conductors inside said casing.

BRIEF DESCRIPTION OF THE'D'RAWING 2 Purely by way of a non-limiting illustration, an example of acold containeraccording tothe invention will be*described with a single FIGURE for reference, whichiis a sectional view thereof.

7 1 DE SCRIPTION OF'THEPREFERRED EMBODIMENT conductors has been limited to four by way of an example:

A metal screen 2 is inserted between the conductors 4 and the casing 1. This screen is metallurgically connected to the inner face of the cold container. It is made of material having a resistivity of less than 31.10 ohms. meter, for example, aluminum.

The screen and the envelope can be made of a laminated strip comprising a first layer consisting of the above-mentioned iron andnickel alloy, and a second layer covering the first and made of aluminum. This strip is bent then welded at 3 when its two edges are face to face after bending. The strip is bent so that the 1 and nickel alloy having an invariable length is subjected to longitudinal mechanical stresses limited to about 6 kg/squ.m, consistent with the mechanical properties of that alloy. The thickness of aluminum remaining ,ce-

mented is then subjected to regularly distributed creeping. and to longitudinal mechanical stresses in ,the vicinity of 3.2 kg/squ.m, which represent. the proof stress of aluminum at the temperature of the .cryogenic connection. The longitudinal tensile stresses on that composite rectilinear container enable it to be usedin cryogenic connections.

The principle of the tensioning of a cylindrical rectilinear container having a great length, made of an alloy having slight thermal contraction such as INVAR has been described in French Patent No. 11,07,609 in the name of the applicant. This principle may be applied to the case of the composite container which has just been described.

' This composite cylindrical container makes it possible to provide the advantages connected with containers made of an alloy whose relative thermal contraction is less than 5.10"

No expansion bellows;

Possibility of continuous production, on the cryogenic connection laying ground. On the other hand, the electric screen enablesv the cancelling of losses by induced currents in containers having high resistivity and more particularly in containers made of INVAR or an alloy having the same technical characteristics.

What is claimed is:

I. In a cold container made of a composite-material, having a tubular shape, surrounding the conductors-of a cryogenic connection, comprising a casing madeof an iron and nickel alloy in which the concentration of nickel comprises between thirtyand forty-five per cent, the improvement wherein: a metal screen made of a material having a resistivity-lower than 3.10" ohms. meter surrounds the conductors inside the said casing.

I 2. The 'cold container according to claim 1, wherein: screen.

said Screen comprises a metal layer Covering the d 4. The cold container according to claim 2, wherein:

ofthe l said material forming the said screen comprises one 3. The cold contalner according to claim 2, wherem:

Said casing and the Said screen are made from a 5 material chosen from the group consisting ofalumrnum laminated and bent strip comprising a first layer formand copper ing said envelope and a second layer forming said 

1. In a cold container made of a composite material, having a tubular shape, surrounding the conductors of a cryogenic connection, comprising a casing made of an iron and nickel alloy in which the concentration of nickel comprises between thirty and forty-five per cent, the improvement wherein: a metal screen made of a material having a resistivity lower than 3.10 8 ohms. meter surrounds the conductors inside the said casing.
 2. The cold container according to claim 1, wherein: said screen comprises a metal layer covering the inside face of the said casing.
 3. The cold container according to claim 2, wherein: said casing and the said screen are made from a laminated and bent strip comprising a first layer forming said envelope and a second layer forming said screen. 